Line 79: |
Line 79: |
| | | |
| | | |
− | ===Ischaemia=== | + | ===[[Muscle Ischaemia]]=== |
| | | |
− | *Firstly [[Muscles Degenerative - Pathology#Necrosis|segmental necrosis]]
| |
− | *-> death of satellite cells
| |
− | **Causes [[Muscle Regeneration|regeneration]] but myoblast precursors have to be recruited from viable fibres
| |
− | *-> death of all cells
| |
− | *Mostly healed by fibrosis and scar formation
| |
− | *May attempt regeneration by [[Muscle Regeneration|budding]]
| |
− | Main causes:
| |
− | *'''Vascular occlusion'''
| |
− | **Infarction from embolism is rare due to collateral circulation
| |
− | **Extension of infarcts depends on size of vessels occluded
| |
− | ***Small capillaries -> segmental [[Muscles Degenerative - Pathology#Necrosis|necrosis]]
| |
− | ***Large arteries -> whole muscle areas, including sattelite cells, are killed
| |
− | **Healed by fibrosis
| |
− | **May be due to:
| |
− | ***Blockage of iliac arteries by aortic-iliac thrombosis in horses
| |
− | ***Blockage of aortic bifurcation in cats
| |
− | ***[[Dirofilaria immitis|''Dirofilaria immitis'']] arteritis in dogs
| |
− | ***Vasculitis due to [[Reoviridae#Bluetongue Virus|bluetongue virus]] in sheep
| |
− | ***[[Haemorrhage#Purpura haemorrhagica|'''Equine purpura haemorrhagica''']]
| |
− | ****Non-contagious, sporadic
| |
− | ****Grossly:
| |
− | *****Subcutaneous oedema
| |
− | *****Scattered haemorrhagic foci throughout skin and muscles
| |
− | *****Vasculitis -> infarcts of muscles
| |
− | ****May cause myoglobinuria if extensive
| |
− | ****Possibly immune mediated
| |
− | ****In horses post [[:Category:Streptococcus species|streptococal]] infection, especially [[Respiratory Bacterial Infections - Pathology#Strangles|strangles]]
| |
− | *'''External pressure'''
| |
− | **During prolonged recumbency, e.g. anaesthesia, inability to rise, or due to too tightly fitting bandages or casts
| |
− | **Post anaesthesia myopathy especially in horses
| |
− | ***Dorsal recumbancy -> gluteals and longissimus ischaemia
| |
− | ***Lateral recumbancy -> triceps brachii, pectoralis, deltoideus and brachiocephalicus ischaemia
| |
− | **Caused by pressure on muscle > perfusion pressure of capillaries
| |
− | **Downer cows - vetral recumbency -> ischaemia of pectoral muscles and muscles of limbs tucked under the animal
| |
− | **Pregnant ewes with twins or triplets -> internal abdominal oblique muscle ischaemic necrosis -> potential rupture
| |
− | *'''Muscle swelling''' where it cannot expand
| |
− | **E.g. supracoracoid muscle infarction in some breeds of turkeys after flapping their wings
| |
− | ***Surrounded by inelastic fascial sheath and bone
| |
− |
| |
− |
| |
− | [[Category:Muscles - Degenerative Pathology]]
| |
| | | |
| ==Trauma== | | ==Trauma== |